CS8421
32-Bit, 192-kHz Asynchronous Sample Rate Converter
Features
175-dB Dynamic Range Bypass Mode
Time Division Multiplexing (TDM) Mode
140-dB THD+N
Attenuates Clock Jitter
No Programming Required
Multiple Device Outputs are Phase Matched
No External Master Clock Required
Linear Phase FIR Filter
Supports Sample Rates up to 211 kHz
Automatic Soft Mute/Unmute
Input/Output Sample Rate Ratios of 7.5:1 to 1:8
+2.5-V Digital Supply (VD)
Master Clock Support for 128 x Fs, 256 x Fs, +3.3-V or 5.0-V Digital Interface (VL)
384 x Fs, and 512 x Fs (Master Mode)
Space-saving 20-pin TSSOP and QFN
Packages
16-, 20-, 24-, or 32-bit Data I/O
The CS8421 supports sample rates up to 211 kHz and
32-bit Internal Signal Processing
is available in 20-pin TSSOP and QFN packages in both
Dither Automatically Applied and Scaled to
Commercial (-10 to +70C) and Automotive (-40 to
Output Resolution
+85C and -40 to +105C) grades. The CDB8421 Cus-
Flexible 3-wire Serial Digital Audio Input and
tomer Demonstration board is also available for device
Output Ports
evaluation and implementation suggestions. See Or-
Master and Slave Modes for Both Input and dering Information on page 35 for complete details.
Output
RST BYPASS
Level Translators
TDM_IN
SDIN
Time
Serial Serial SDOUT
Varying
Data
ISCLK Audio Audio
Data
Digital
Data
Input Output
OSCLK
Filters
Sync Info
ILRCK
Sync Info
OLRCK
Digital
SRC_UNLOCK
PLL
MS_SEL Clock
MCLK_OUT
Serial
Generator
Port
SAIF
Mode
Decoder
SAOF
3.3 V or 5.0 V (VL) 2.5 V (VD) GND XTI XTO
Copyright Cirrus Logic, Inc. 20042015
DS641F7
(All Rights Reserved)
AUG 15
CS8421
General Description
The CS8421 is a 32-bit, high-performance, monolithic CMOS stereo asynchronous sample-rate converter.
Digital audio inputs and outputs can be 32, 24, 20, or 16 bits. Input and output data can be completely asynchronous,
synchronous to an external data clock, or the part can operate without any external clock by using an integrated
oscillator.
Audio data is input and output through configurable 3-wire input/output ports. The CS8421 does not require any soft-
ware control via a control port.
Target applications include digital recording systems (DVD-R/RW, CD-R/RW, PVR, DAT, MD, and VTR), digital mix-
ing consoles, high-quality D/A, effects processors, computer audio systems, and automotive audio systems.
The CS8421 is also suitable for use as an asynchronous decimation or interpolation filter. See Cirrus Logic Appli-
cation Note AN270, Audio A/D Conversion with an Asynchronous Decimation Filter, available at www.cirrus.com
for more details.
2 DS641F7